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                            <div style="color:gray; word-break: break-all; font-size:12px;">原英文版地址: <a href="https://www.elastic.co/guide/en/elasticsearch/reference/7.7/analysis-ngram-tokenfilter.html" rel="nofollow" target="_blank">https://www.elastic.co/guide/en/elasticsearch/reference/7.7/analysis-ngram-tokenfilter.html</a>, 原文档版权归 www.elastic.co 所有<br/>本地英文版地址: <a href="../en/analysis-ngram-tokenfilter.html" rel="nofollow" target="_blank">../en/analysis-ngram-tokenfilter.html</a></div>
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<span class="breadcrumb-node">N-gram token filter</span>
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<h2 class="title">
<a id="analysis-ngram-tokenfilter"></a>N-gram token filter<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/ngram-tokenfilter.asciidoc">edit</a>
</h2>
</div></div></div>

<p>Forms <a href="https://en.wikipedia.org/wiki/N-gram" class="ulink" target="_top">n-grams</a> of specified lengths from
a token.</p>
<p>For example, you can use the <code class="literal">ngram</code> token filter to change <code class="literal">fox</code> to
<code class="literal">[ f, fo, o, ox, x ]</code>.</p>
<p>This filter uses Lucene’s
<a href="https://lucene.apache.org/core/8_5_1/analyzers-common/org/apache/lucene/analysis/ngram/NGramTokenFilter.html" class="ulink" target="_top">NGramTokenFilter</a>.</p>
<div class="note admon">
<div class="icon"></div>
<div class="admon_content">
<p>The <code class="literal">ngram</code> filter is similar to the
<a class="xref" href="analysis-edgengram-tokenfilter.html" title="Edge n-gram token filter"><code class="literal">edge_ngram</code> token filter</a>. However, the
<code class="literal">edge_ngram</code> only outputs n-grams that start at the beginning of a token.</p>
</div>
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<div class="titlepage"><div><div>
<h3 class="title">
<a id="analysis-ngram-tokenfilter-analyze-ex"></a>Example<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/ngram-tokenfilter.asciidoc">edit</a>
</h3>
</div></div></div>
<p>The following <a class="xref" href="indices-analyze.html" title="Analyze API">analyze API</a> request uses the <code class="literal">ngram</code>
filter to convert <code class="literal">Quick fox</code> to 1-character and 2-character n-grams:</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">GET _analyze
{
  "tokenizer": "standard",
  "filter": [ "ngram" ],
  "text": "Quick fox"
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/962.console"></div>
<p>The filter produces the following tokens:</p>
<div class="pre_wrapper lang-text">
<pre class="programlisting prettyprint lang-text">[ Q, Qu, u, ui, i, ic, c, ck, k, f, fo, o, ox, x ]</pre>
</div>
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<div class="section">
<div class="titlepage"><div><div>
<h3 class="title">
<a id="analysis-ngram-tokenfilter-analyzer-ex"></a>Add to an analyzer<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/ngram-tokenfilter.asciidoc">edit</a>
</h3>
</div></div></div>
<p>The following <a class="xref" href="indices-create-index.html" title="Create index API">create index API</a> request uses the <code class="literal">ngram</code>
filter to configure a new <a class="xref" href="analysis-custom-analyzer.html" title="Create a custom analyzer">custom analyzer</a>.</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">PUT ngram_example
{
  "settings": {
    "analysis": {
      "analyzer": {
        "standard_ngram": {
          "tokenizer": "standard",
          "filter": [ "ngram" ]
        }
      }
    }
  }
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/963.console"></div>
</div>

<div class="section">
<div class="titlepage"><div><div>
<h3 class="title">
<a id="analysis-ngram-tokenfilter-configure-parms"></a>Configurable parameters<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/ngram-tokenfilter.asciidoc">edit</a>
</h3>
</div></div></div>
<div class="variablelist">
<dl class="variablelist">
<dt>
<span class="term">
<code class="literal">max_gram</code>
</span>
</dt>
<dd>
(Optional, integer)
Maximum length of characters in a gram. Defaults to <code class="literal">2</code>.
</dd>
<dt>
<span class="term">
<code class="literal">min_gram</code>
</span>
</dt>
<dd>
(Optional, integer)
Minimum length of characters in a gram. Defaults to <code class="literal">1</code>.
</dd>
</dl>
</div>
<p>You can use the <a class="xref" href="index-modules.html#index-max-ngram-diff"><code class="literal">index.max_ngram_diff</code></a> index-level
setting to control the maximum allowed difference between the <code class="literal">max_gram</code> and
<code class="literal">min_gram</code> values.</p>
</div>

<div class="section">
<div class="titlepage"><div><div>
<h3 class="title">
<a id="analysis-ngram-tokenfilter-customize"></a>Customize<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/analysis/tokenfilters/ngram-tokenfilter.asciidoc">edit</a>
</h3>
</div></div></div>
<p>To customize the <code class="literal">ngram</code> filter, duplicate it to create the basis for a new
custom token filter. You can modify the filter using its configurable
parameters.</p>
<p>For example, the following request creates a custom <code class="literal">ngram</code> filter that forms
n-grams between 3-5 characters. The request also increases the
<code class="literal">index.max_ngram_diff</code> setting to <code class="literal">2</code>.</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">PUT ngram_custom_example
{
  "settings": {
    "index": {
      "max_ngram_diff": 2
    },
    "analysis": {
      "analyzer": {
        "default": {
          "tokenizer": "whitespace",
          "filter": [ "3_5_grams" ]
        }
      },
      "filter": {
        "3_5_grams": {
          "type": "ngram",
          "min_gram": 3,
          "max_gram": 5
        }
      }
    }
  }
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/964.console"></div>
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